This invention relates generally to turbine engines, and, more particularly, to fuel connections within turbine engines.
A gas turbine engine typically includes a combustor that has a manifold assembly for supplying fuel to a combustion chamber. Fuel manifold assemblies include a plurality of circumferentially spaced fuel nozzles. Each fuel nozzle is coupled to a fuel tube that is connected to a fuel manifold ring. The fuel manifold ring is connected to a main fuel inlet tube by at least one fuel line connection.
During operation, the main fuel inlet tube is pressurized and supplies fuel to the fuel manifold ring. Over time, the fuel line connections may develop fuel leaks as a result of continued exposure to the increased pressure of the main fuel inlet tube. Such fuel leaks may impinge on hot engine components and auto-ignite causing potential damage to engine components.
To prevent fuel leaking from the fuel line connections and impinging on hot engine components, such connections typically include fuel line connection encapsulation devices. Known encapsulation devices include spray shields having a symmetric first portion sized to receive the fuel line connection. The first portion also includes a plurality of attachment projections and a drain opening for channeling fuel contained within the first portion away from the engine. The second portion is sized to receive the first portion and includes a plurality of openings that are sized to receive the attachment projections for securing the second portion to the first portion. Because the first portion is symmetric, the first portion may be secured to the second portion in several different orientations. As a result, the first portion may be installed such that the drain opening is oriented to permit fuel to drain from the first portion either towards the engine components or away from the engine components.
In an exemplary embodiment, a gas turbine engine combustor includes a spray shield that attaches to the fuel manifold assembly such that potential fuel leaks that develop from fuel line connections are directed away from engine components. The fuel line connections attach a main fuel inlet tube to a fuel manifold ring and the spray shield encapsulates the fuel line connections to prevent any fuel leaking from the fuel line connections from impinging on engine components. Each spray shield includes a first portion and a second portion that is sized to be received within the first portion in only one orientation. The first portion includes at least two retention straps and the second portion includes at least one attachment projection and a pair of drain openings. The retention straps and the attachment projection permit the second portion to be secured to the first portion in only one orientation. The first portion also includes a fuel collar that extends from a sidewall circumscribing the first portion.
During engine operation, potential fuel leaks that occur at the fuel line connections are contained within the spray shield second portion. The fuel is gravity-drained from the spray shield through a pair of openings within the second portion and is directed towards the bottom of the engine and away from engine components. Furthermore, although the fuel is pressurized, the fuel collar prevents the fuel from inadvertently escaping the spray shield through a fuel line opening. Accordingly, a potential of autoignition or spontaneous combustion as a result of fuel impinging upon a hot engine component is reduced.